Heat oven to 180 degrees celsius. Line a 20 x 30cm baking tray tin with baking parchment. Put the chocolate, butter and sugar in a pan and gently melt, stirring occasionally with a wooden spoon. Remove from heat.
Stir in eggs into the melted chocolate mixture. Sieve over the flour and cocoa and stir in. Then stir in half the raspberries then pour batter into tray. Scatter over the remaining raspberries.
Bake on the middle shelf for 30 minutes. Cool before slicing into squares.